Acrylic acid derivatives of perfluoroalkyl alcohols (e.g., CF3(CF2)7CH2CH2OCOCH═CH2) are used in large amounts as monomers for synthesizing water- and oil- repellents for textile. Moreover, perfluoroalkyl alcohols serving as starting materials of the acrylates are widely used as, for example, surfactants (see Patent Document 1).
Such compounds having a perfluoroalkyl group as a structural unit are generally known to be able to improve surface modification properties, water- and oil-repellency, antifouling properties, mold-release properties, leveling properties, and other properties, when applied on the surfaces of fiber, metal, glass, rubber, resin, etc. Particularly, compounds having a C8-C12 perfluoroalkyl group (telomer compounds) are most likely to develop the aforementioned desired performance, and therefore, C8 telomer compounds are particularly preferably used.
On the other hand, it is reported that in particular, telomer compounds having a C8-C12 perfluoroalkyl group are biologically degraded in the environment and converted to compounds having relatively high bioaccumulative and environmental concentration, causing concerns for exposure during treatment processes, and release or diffusion from waste, treated substrates, etc., into the environment. Moreover, compounds having a perfluoroalkyl group containing 14 or more carbon atoms are very difficult to handle because of their physicochemical properties, and hence, such compounds are rarely used in practice.
As for telomer compounds having a perfluoroalkyl group containing 8 or more carbon atoms, generation and incorporation of perfluorooctanoic acids with high bioaccumulation potential is unavoidable during the production of the telomer compounds.
For these reasons, companies that produce such telomer compounds have retreated from the production of the compounds or promoted the use of alternative compounds having a perfluoroalkyl group containing 6 or less carbon atoms. However, compounds having a perfluoroalkyl group containing 6 or less carbon atoms cause a significant decrease in orientation on the surface of a treated substrate, and the melting point, glass transition point, etc., of the compounds are markedly lower than those of C8 compounds. Accordingly, the compounds are highly influenced by their using environmental conditions, such as temperature, humidity, stress, and the organic solvent, and the desired performance cannot be sufficiently achieved. In addition, durability and other properties are affected.